PT0E-1368

Portable Multi-Gas Monitor

RX-8500/RX-8700
Operating Manual(PT0-136)

Contents
1 Outline of the Product...................................................................................................................................... 4
Preface ............................................................................................................................................................ 4
Purpose of use ................................................................................................................................................ 4
Definition of DANGER, WARNING, CAUTION and NOTE ............................................................................ 5
Method of confirmation for Standards and Explosion proof specification ...................................................... 5
2. Important Notices on Safety ........................................................................................................................... 6
2-1. Danger cases........................................................................................................................................... 6
2-2. Warning cases ......................................................................................................................................... 8
2-3. Precautions .............................................................................................................................................. 9
2-4. Safety Information ................................................................................................................................. 11
3. Product Components .................................................................................................................................... 12
3-1. Main unit and standard accessories ...................................................................................................... 12
Main unit .................................................................................................................................................... 12
Accessories ............................................................................................................................................... 13
3-2. Names and functions for each part ....................................................................................................... 16<RX-8500 (with lithium ion battery unit BUL-8000(Z1))> ......................................................................... 16<RX-8700 (with lithium ion battery unit BUL-8000)> ................................................................................ 19
4. How to Use ................................................................................................................................................... 23
4-1. Before using the gas monitor ................................................................................................................ 23
4-2. Preparation for start-up ......................................................................................................................... 23
4-2-1. Charging the lithium ion battery unit (BUL-8000(Z1)) .................................................................... 24
4-2-2. Detaching and attaching the battery unit........................................................................................ 25
4-2-3. Attaching batteries to the dry battery unit (BUD-8000(Z), option) .................................................. 26
4-2-4. Connecting the gas sampling probe and gas sampling hoses ...................................................... 27
4-3. How to start the gas monitor ................................................................................................................. 29
4-3-1. Power-on ........................................................................................................................................ 29
4-3-2. Switching the hydrogen sulfide measuring mode range on RX-8700 ............................................ 31
4-4. Basic operating procedures................................................................................................................... 32
4-4-1. RX-8500 basic operating procedures ............................................................................................. 32
4-4-2. RX-8700 basic operating procedures ............................................................................................. 33
4-5. Measurement ......................................................................................................................................... 34
4-5-1. Gas concentration measurement ................................................................................................... 34
4-5-2. Range switching point .................................................................................................................... 36
4-6. Air calibration ......................................................................................................................................... 37
4-6-1. Attaching the CO2 removal filter (RX-8500) ................................................................................... 37
4-6-2. Air calibration procedure ................................................................................................................. 38
4-7. Manual memory ..................................................................................................................................... 41
4-8. Stopping the pump (PUMP OFF mode) ................................................................................................ 42
4-9. Power-off ............................................................................................................................................... 43
5. Setting Procedure ......................................................................................................................................... 44
5-1. Display/setting mode ............................................................................................................................. 44
5-2. PEAK display/clear ................................................................................................................................ 46
5-3. Full scale/alarm setpoint display/gas alarm test (optional function) ..................................................... 47
5-4. Station ID display................................................................................................................................... 48
5-5. Log data display .................................................................................................................................... 49
6. Fault Alarm Function .................................................................................................................................... 50
Fault alarm activation .................................................................................................................................... 50
7. Maintenance ................................................................................................................................................. 52
7-1. Maintenance intervals and items ........................................................................................................... 52
About maintenance services ..................................................................................................................... 53
7-2. Span adjustment .................................................................................................................................... 54
7-2-1. Preparation ..................................................................................................................................... 54
7-2-2. How to connect ............................................................................................................................... 54
7-2-3. Span adjustment procedure ........................................................................................................... 55
7-3. How to clean .......................................................................................................................................... 58
7-4. Parts replacement ................................................................................................................................. 59
7-4-1. Sensor replacement ....................................................................................................................... 59
7-4-2. Replacement procedure for gas sampling probe dust filter ........................................................... 59
7-4-3. Replacement procedure for filter tube dust filter ............................................................................ 60
7-4-4. Replacement procedure for filter tube absorbent cotton ................................................................ 60-2-

7-4-5. Replacement of regular replacement parts .................................................................................... 61
8. Storage and Disposal ................................................................................................................................... 62
8-1. Procedures to store the gas monitor or leave it for a long time ......................................................... 62
8-2. Procedures to use the gas monitor again ............................................................................................. 62
8-3. Disposal of products .............................................................................................................................. 63
9. Troubleshooting ............................................................................................................................................ 64
9-1. Abnormalities on unit ............................................................................................................................. 64
9-2. Abnormalities of readings ...................................................................................................................... 66
10. Product Specifications ................................................................................................................................ 67
10-1. RX-8500 specifications ........................................................................................................................ 67
10-1-1. List of RX-8500 specifications ...................................................................................................... 67
10-1-2. RX-8500 standard accessories .................................................................................................... 68
10-2. RX-8700 specifications ........................................................................................................................ 69
10-2-1. List of RX-8700 specifications ...................................................................................................... 69
10-2-2. RX-8700 standard accessories .................................................................................................... 70
10-3. List of optional items ............................................................................................................................ 71
11. Appendix ..................................................................................................................................................... 72
11-1. Definition of terms ................................................................................................................................ 72
11-2. Calibration history/various trend/event history functions..................................................................... 72
11-3. Gas alarm (optional function) .............................................................................................................. 74-3-

1 Outline of the ProductPreface11Outline of the ProductPrefaceThank you for choosing our portable multi-gas monitor RX-8500/RX-8700 (hereinafter referred to as"gas monitor"). Please check that the model number of the product you purchased is included in thespecifications on this manual.
This manual describes how to use the monitor properly and its specifications. Not only the first-timeusers but also the users who have already used the gas monitor must read and understand theoperating manual and use this product as described in this manual.
Note that the contents of this manual are subject to change without notice for product improvement.
Also, any copying or reproduction of this manual, in whole or in part, without permission is prohibited.
Regardless of warranty period, we shall not make any indemnification for accidents and damage
caused by using the gas monitor.
Make sure to read the warranty policy specified on the warranty.

Purpose of use
This product is a portable gas monitor capable of measuring multiple gases alone, which is required in
LNG carriers or oil tankers. Measurable gases and ranges are shown below.
<RX-8500>
Measuring gas
Combustible gas (CH4)
Oxygen (O2)
Carbon monoxide (CO)Carbon dioxide (CO2)

Measuring range <Service range>
0 - 100.0 %LEL/5 - 100.0 vol%0 - 25.0 % <25.1 - 40.0 %>0 - 1000 ppm
0 - 20.0 vol%<RX-8700>
Measuring gas
Combustible gas (HC)*Oxygen (O2)

Measuring range <Service range>
0 - 100.0 %LEL/2 - 100.0 vol%0 - 25.0 % <25.1 - 40.0 %>Hydrogensulfide (H2S)

0 - 30.0 ppm <30.5 - 100.0 ppm>
0 - 1000 ppm[Low concentration][High concentration]* HC: Isobutane converted
RX-8500 is capable of measuring CH4 (methane) as combustible gas, whereas RX-8700 is capable ofmeasuring general combustible gases HC (isobutane converted).

-4-1 Outline of the ProductDefinition of DANGER, WARNING, CAUTION and NOTE

Note that measurement results of the gas monitor are not intended to guarantee life or safety in any
way.
Check the specifications before use and conduct gas measurement properly in accordance withpurposes.
In addition to this operating manual, an operating manual for the data logger management program(option) is available for the gas monitor. Please contact RIKEN KEIKI if it is needed.

Definition of DANGER, WARNING, CAUTION and NOTE
Throughout this manual, the following indications are used to ensure safe and effective work.

DANGER

This message indicates that improper handling may cause serious
damage on life, health or assets.

WARNING

This message indicates that improper handling may cause serious
damage on health or assets.

CAUTION

This message indicates that improper handling may cause minor
damage on health or assets.

NOTE

This message indicates advice on handling.

Method of confirmation for Standards and Explosion
proof specification
This instrument has some specification depends on standard and explosion proof certificate. Pleaseconfirm the detector specification before using. Please refer Declaration of Conformity that is at the end of
this manual if you have CE/UKCA marking type. You can confirm instrument specification to see nameplate as follows.

ATEX/IECEx/UKEX certificate
Ex marking
CE marking
UKCA marking

Japan Ex certificate

Type name plate-5-2. Important Notices on Safety

2-1. Danger cases

22.

Important Notices on
SafetyTo maintain the performance and use the gas monitor safely, observe the following instructions of
DANGER, WARNING and CAUTION.

2-1. Danger cases
DANGER
About explosion-proof
 Do not modify or change the circuit, structure, etc.
 When using the gas monitor in a hazardous area, take the following countermeasures forpreventing dangers resulting from electrostatic charges.
(1) Wear anti-static clothes and conductive shoes (anti-static work shoes).
(2) For indoor use, use the gas monitor while standing on a conductive work floor (with aleakage resistance of 10 MΩ or less).
 [RX-8500, RX-8700] When measuring the oxygen concentration, do not measure anything but
a mixture of air and combustible gases or vapors and toxic gases.
 [RX-8500, RX-8700] Connect either the dry battery unit BUD-8000(Z)(TC21187) or lithium ion
battery unit BUL-8000(Z1)(TC21188).
 [BUD-8000(Z), BUL-8000(Z1)] Connect either RX-8500 or RX-8700(TC21186) unit.
 [BUD-8000(Z), BUL-8000(Z1)] Replace the battery unit in a safe place.
 [BUL-8000(Z1)] Charge the battery unit using the dedicated AC adapter in a safe place.
 [BUL-8000(Z1)] Charge the battery unit at ambient temperatures between 0 - 40ºC.
 [BUD-8000(Z)] Replace the batteries in a safe place.
 [BUD-8000(Z)] The explosion-proof standard for the gas monitor requires the use of TOSHIBA
dry batteries. Use three Alkaline AA batteries, type LR6 manufactured by Toshiba to use thegas monitor as an explosion-proof unit.
 The specifications of RX-8500 and RX-8700 are as follows:
Pump circuit: Allowable voltage of 4.95 V, allowable current of 1.12 A and allowable
power of 1138 mW
Infrared detection circuit : Allowable voltage of 4.95 V, allowable current of 0.834 A andallowable power of 853 mW
Buzzer circuit: Allowable voltage of 4.95 V, allowable current of 0.431 A andallowable power of 441 mW
Main circuit: Allowable voltage of 4.95 V, allowable current of 0.717 A andallowable power of 733 mW
Backup circuit: 3.0 VDC, 10 µA
Ambient temperature: -20 - +50 ºC-6-

2. Important Notices on Safety

2-1. Danger cases

DANGER
About explosion-proof The specifications of BUL-8000(Z1) are as follows:
Pump circuit: Maximum voltage of 4.25 V, maximum current of 1.12 A andmaximum power of 901 mW
Infrared detection circuit : Maximum voltage of 4.25 V, maximum current of 0.768 A andmaximum power of 618 mW
Buzzer circuit: Maximum voltage of 4.25 V, maximum current of 0.410 A andmaximum power of 330 mW
Main circuit: Maximum voltage of 4.25 V, maximum current of 0.653 A andmaximum power of 526 mW
Battery charging contact : Allowable voltage of 250 VAC, 50/60 Hz
Ambient temperature: -20 - +50 ºC
 The specifications of BUD-8000(Z) are as follows:
Pump circuit: Maximum voltage of 4.95 V, maximum current of 1.12 A andmaximum power of 1138 mW
Infrared detection circuit : Maximum voltage of 4.95 V, maximum current of 0.834 A andmaximum power of 853 mW
Buzzer circuit: Maximum voltage of 4.95 V, maximum current of 0.431 A andmaximum power of 441 mW
Main circuit: Maximum voltage of 4.95 V, maximum current of 0.717 A andmaximum power of 733 mW
Power supply: 4.5 V 150 mA (Type LR6 manufactured by Toshiba, 3 pcs)
Ambient temperature: -20 - +50 ºC
 Make sure that the product model on the nameplate is correct.
Inappropriate combinations of models deviate from the range of explosion-proof certification.
 The nameplate shows the followings as well as the product model.
Product model : Main unit: RX-8500, 8700
Lithium ion battery unit: BUL-8000(Z1)Dry battery unit: BUD-8000 (Z)Explosion proof class : 【RX-8500,8700】Ex ia IIC T4X【BUL-8000(Z1), BUD-8000(Z)】 Ex ia IIC T4
Ambient temperature : -20 - 50 ºC
Charging terminal rating : 【BUL-8000(Z1)】Allowable voltage AC250V 50/60Hz
Warnings : 【BUL-8000(Z1), BUD-8000(Z)】Inhibit to take off battery unit in non-hazardous area.
 Manufacturer : RIKEN KEIKI Co., Ltd.
 IP protection class: IP20
Name plate

Name plate

About use While conducting measurement in a manhole or confined space, do not lean over or look into
the manhole or confined space. It may lead to dangers because oxygen-deficient air or othergases may blow out.
 Oxygen-deficient air or other gases may be discharged from the gas exhausting outlet (GAS
OUT). Never inhale the air or gases.
 High-concentration (100 %LEL or higher) gases may be discharged. Never use fire near it.

-7-

2. Important Notices on Safety

2-2. Warning cases

2-2. Warning cases
WARNING
Sampling point pressure The concentration meter is designed to draw gases under the atmospheric pressure. If
excessive pressure is applied to the gas inlet (GAS IN) and outlet (GAS OUT) of the gas
monitor, measured gases may leak out from its inside and may cause dangerous conditions.
Be sure that excessive pressure is not applied to them while used.
 Do not connect the gas sampling hose directly to a location with a pressure higher than theatmospheric pressure. The internal piping system may be damaged.
Handling of sensor
 Do not disassemble the carbon monoxide, hydrogen sulfide or oxygen sensor inside the gas
monitor because it contains electrolyte. Electrolyte may cause severe skin burns if it contacts
skin, while it may cause blindness if its contacts eyes.
If electrolyte is adhered on your clothes, that part on your clothes is discolored or its material isdecomposed. If contact occurs, rinse the area immediately with a large quantity of water.
Air calibration in atmosphere When air calibration is performed in the atmosphere, check the atmosphere for freshness
before beginning it. If interference gases exist, air calibration cannot be performed properly,
thus causing erroneous measurement and leading to dangers when the gas leaks.
Battery level check Before use, check that there remains sufficient battery power. When the gas monitor is used forthe first time or is not used for a long period, the batteries may be exhausted. Replace themwith new ones before use.
 If a low battery voltage alarm is triggered, gas measurement cannot be conducted. If the alarmis triggered during use, turn off the power and promptly replace the batteries in a safe area.
Others Do not throw the gas monitor into fire.
 Do not wash the gas monitor in a washing machine or ultrasonic cleaner.
 Do not block the buzzer sound opening. No alarm sound can be heard.
 Do not remove batteries while the power is on.
 Do not vibrate or give a shock to the gas monitor by, for example, relocating the gas monitor
with an optional water trap attached. The gas inlet (GAS IN) may be damaged.

-8-

2. Important Notices on Safety

2-3. Precautions

2-3. Precautions
CAUTION
Do not use the gas monitor in a place where it is exposed to oil, chemicals, etc. Do notsubmerge the gas monitor under water on purpose.
 Do not use in a place where the gas monitor is exposed to liquids such as oil and chemicals.
 The gas monitor is not water-pressure-resistant. Avoid using it in a place where a high waterpressure is applied to it (under a faucet, shower, rainfall, etc.) or submerging it under water fora long time. Note that the gas monitor is water-proof only in fresh water and running water, andnot in hot water, salt water, detergent, chemicals, human sweat, etc.
 The gas inlet (GAS IN) and outlet (GAS OUT) are not water-proof. Be careful not to let watersuch as rainwater get into these parts. Because this may cause trouble and gas cannot bemeasured.
 Do not place the gas monitor where water or dirt gets accumulated. The gas monitor placed atsuch a location may malfunction due to water or dirt that gets into the buzzer sound opening,gas inlet (GAS IN), etc.
 Note that drawing in dirty water, dust, metallic powder, etc. will significantly deteriorate thesensor sensitivities. Be careful when the gas monitor is used in an environment where theseelements exist.
Do not use the gas monitor in a place where the temperature drops below -20 ºC or rises over
50 ºC.
 The operating temperature of the gas monitor is -20 °C - +50 °C. Do not use the gas monitor at
higher temperatures, humidities and pressures or at lower temperatures than the operating
range.
 Avoid long-term use of the gas monitor in a place where it is exposed to direct sunlight.
 Do not store the gas monitor in a sun-heated car.
Observe the operating restrictions to prevent condensation inside the gas monitor or gas
sampling hose.
 Condensation formed inside the gas monitor or gas sampling hose causes clogging or gas
adsorption, which may disturb accurate gas measurement. Thus, condensation must be
avoided. In addition to the installation environment, carefully monitor the temperature/humidityof the sampling point to prevent condensation inside the gas monitor. Please observe theoperating restrictions.
Do not use a transceiver near the gas monitor.
 Radio wave from a transceiver or the like near the gas monitor may disturb the readings. If atransceiver or other radio wave transmitting device is used, it must be used in a place awayfrom the gas monitor where it disturbs nothing.
 Do not use the gas monitor near a device that emits strong electromagnetic waves(high-frequency or high-voltage devices).
Verify that the pump driving indicator is rotating before using the gas monitor
 If the pump driving indicator is not rotating, gas measurement cannot be performed properly.
Check whether the flow rate is lost.
Never fail to perform a regular maintenance.
 The gas monitor is a safety unit. Never fail to perform regular maintenance. Continuing to use
the gas monitor without performing maintenance will compromise the sensitivity of the sensor,
thus resulting in inaccurate gas measurement.

-9-2. Important Notices on Safety

2-3. Precautions

CAUTION
Others Pressing switches unnecessarily may change the settings, preventing alarms from activatingcorrectly. Operate the gas monitor using only the procedures described in this operating
manual.
 Do not drop or give shock to the gas monitor. The accuracy of the gas monitor may be
deteriorated.
 Do not use the gas monitor while charging it.
 Whereas the gas monitor can measure combustible gases, carbon monoxide, carbon dioxide,hydrogen sulfide and oxygen, the measurement environment may include gases that have
harmful effects on the sensors of this unit.
 When measuring concentrations of oxygen in inert gases for a long time, the carbon dioxide
concentration in the air must be 15 vol% or less. When the gas monitor is used in the inert gas
with a carbon dioxide concentration higher than 15 vol%, perform measurement in as shorttime as possible.
 Do not use the gas monitor in a place with high oxygen concentration for a long time. The
oxygen sensor life may be shortened.
 Do not jab the buzzer sound opening with a sharp-pointed item. The gas monitor may
malfunction or get damaged, allowing foreign matter, etc. to get inside.
 Do not remove the panel sheet on the LCD display. The dust-proof performance will be
deteriorated.
 Do not affix a label or the like on the infrared port. Infrared communications can no longer be
conducted.
Replacement of batteries
 Turn off the power of the gas monitor before replacing the batteries.
 Replace all of the three batteries with new ones at one time.
 The explosion-proof standard for the gas monitor requires the use of TOSHIBA dry batteries(only when the dry battery unit is used). Use three Alkaline AA batteries, type LR6
manufactured by Toshiba to use the gas monitor as an explosion-proof unit.
 Pay attention to the polarities of the batteries.
Usage In a low-temperature environment, the operating time is shortened due to the battery
performance property.
 At low temperatures, the responses of the LCD display may slow down.
 Perform air calibration under pressure and temperature/humidity conditions close to those in
the operating environment and in fresh air.
 Perform air calibration after the reading is stabilized.
 If there is a sudden temperature change of 15 ºC or more between the storage and operational
locations, turn on the power of the gas monitor, let it stand for about 10 minutes in a similar
environment to the operational location, and perform air calibration in fresh air before using it.
 When cleaning the gas monitor, do not splash water over it or use organic solvents such as
alcohol and benzene on it. The surface of the gas monitor may be discolored or damaged.
 If the gas monitor is not used for a long time, turn on the power at least once every six months
and check that the pump draws in air (about three minutes). The gas monitor, when not
activated for a long time, may cease to work because of hardening of the grease in the pump
motor.
 If the gas monitor is not used for a long time, store it after removing the batteries. Battery leaks
may result in fire, injury, etc.
 When using the gas monitor after long-term storage, never fail to perform air calibration. For
information on readjustment including air calibration, please contact RIKEN KEIKI.

- 10 -

2. Important Notices on Safety

2-4. Safety Information

2-4. Safety Information
The Portable Gas Detector Model RX-8500/8700 is a gas monitors designed to provide continuous exposure
monitoring of combustible gas, Oxygen (O2), toxic gas such as carbon monoxide (CO), Carbon Dioxide(CO2),and hydrogen sulfide (H2S) in hazardous environments. The gas sampling is suctioned by build-in micropump.
The battery can be selected either Li-ion battery or alkaline dry battery.
Li-ion battery unit is called BUL-8000(Z1) and alkaline dry battery unit is called BUD-8000(Z).
The battery unit structured even the end user is possible to replace.
Specification for safety
・Ex ia IIC T4 Ga

・

II 1 G Ex ia IIC T4 Ga

・Ambient temperature range for use ： -20 °C - +50 °C
・Ambient temperature range during battery charging ： 0 °C - +40 °C
Electrical data
・Power supply of Li-ion battery unit : BUL-8000(Z1)
Two parallel connected Li-ion cells used in battery pack BP-8000 are from type Maxell
INR18650PB1 or SDI INR18650-15M or SONY US18650VT3.
Um = 250 V.
・Power supply of alkaline battery unit : BUD-8000(Z)Powered by three series connected Alkaline AA batteries, type LR6 manufactured by Toshiba.
Certificate numbers
・IECEx Certificate number ： IECEx PRE 15.0012
・ATEX Certificate number ： Presafe 15 ATEX6173X
・UK Type Examination Certificate : DNV 22 UKEX 25918X
List of standards
・IEC 60079-0：2017
・EN IEC 60079-0:2018
・BS EN IEC 60079-0:2018
・IEC 60079-11：2011
・EN60079-11:2012
・BS EN 60079-11:2012
Specific conditions of “X”-mark:Regarding ATEX specification, the measuring function according to Annex II paragraph 1. 5. 5 of
the Directive is not covered by this EU-type examination.
It shall comply with the requirements from the relevant European harmonized standards which
provide guidance on the performance of gas detection equipment and safety devices.
The measuring function according to schedule 1, paragraph 24 of the Regulation is not covered inthis UK-type examination. It shall comply with the requirements from the relevant UK DesignatedStandards which provide guidance on the performance of gas detection equipment.
WARNING
・DO NOT CHARGE IN HAZARDOUS LOCATION.
・DO NOT CHARGE IT EXCEPT BY GENUINE CHARGER.
・DO NOT REPLACE BATTERY UNIT IN HAZARDOUS LOCATION.
・DO NOT REPLACE DRY BATTERIES IN HAZARDOUS LOCATION.
・DO NOT ATTEMPT TO DISASSEMBLE OR ALTER THE INSTRUMENT.
・USE ONLY WITH CONNECTED ALKALINE AA BATTERY, TYPE LR6MANUFACTURED BY TOSHIBA.
INST. No. 0 0 0 0 0 0 0 0 0 0 0
AB C
DE
A: Manufacturing year (0-9)
B: Manufacturing month (1-9,XYZ for Oct.-Dec.)
C: Manufacturing lot
D: Serial number
E: Code of factory
Phone
Fax
E-mailWeb site: +81-3-3966-1113: +81-3-3558-9110 GIII
: intdept@rikenkeiki.co.jp: https://www.rikenkeiki.co.jp- 11 -

3. Product Components

3-1. Main unit and standard accessories

3
3.

Product Components

3-1. Main unit and standard accessories
Unpack and check the main unit and accessories.
If any part is missing, contact RIKEN KEIKI.

Main unit
See ʻNames and functions for each partʼ (P. 16) for names and functions of each part of the gas monitor
and LCD display.

<RX-8500 main unit><RX-8700 main unit>- 12 -

3. Product Components

3-1. Main unit and standard accessories

Accessories
Lithium ion battery
unit (BUL-8000): 1 pcAC adapter forcharging: 1 pcFilter tube andrelay tube: 1 pc

Filter tube andrelay tube: 1 pc

Absorbing tube fixing
belt: 2 pcs

Shoulder strap: 1 pcCO2 removal filter(CF-283): 1 pc
(RX-8500 only)

Zero filter fixing belt
: 1 pc (RX-8500 only)

Product warranty
Operating manual- 13 -

3. Product Components

3-1. Main unit and standard accessories

DANGER
About explosion-proof
 Do not modify or change the circuit, structure, etc.
 When using the gas monitor in a hazardous area, take the following countermeasures forpreventing dangers resulting from electrostatic charges.
(1) Wear anti-static clothes and conductive shoes (anti-static work shoes).
(2) For indoor use, use the gas monitor while standing on a conductive work floor (with aleakage resistance of 10 MΩ or less).
 [RX-8500, RX-8700] When measuring the oxygen concentration, do not measure anything but
a mixture of air and combustible gases or vapors and toxic gases.
 [RX-8500, RX-8700] Connect either the dry battery unit BUD-8000(Z)(TC21187) or lithium ion
battery unit BUL-8000(Z1)(TC21188).
 [BUD-8000(Z), BUL-8000(Z1)] Connect either RX-8500 or RX-8700(TC21186) unit.
 [BUD-8000(Z), BUL-8000(Z1)] Replace the battery unit in a safe place.
 [BUL-8000(Z1)] Charge the battery unit using the dedicated AC adapter in a safe place.
 [BUL-8000(Z1)] Charge the battery unit at ambient temperatures between 0 - 40ºC.
 [BUD-8000(Z)] Replace the batteries in a safe place.
 [BUD-8000(Z)] The explosion-proof standard for the gas monitor requires the use of TOSHIBA
dry batteries. Use three Alkaline AA batteries, type LR6 manufactured by Toshiba to use thegas monitor as an explosion-proof unit.
 The specifications of RX-8500 and RX-8700 are as follows:
Pump circuit: Allowable voltage of 4.95 V, allowable current of 1.12 A and allowable
power of 1138 mW
Infrared detection circuit : Allowable voltage of 4.95 V, allowable current of 0.834 A andallowable power of 853 mW
Buzzer circuit: Allowable voltage of 4.95 V, allowable current of 0.431 A andallowable power of 441 mW
Main circuit: Allowable voltage of 4.95 V, allowable current of 0.717 A andallowable power of 733 mW
Backup circuit: 3.0 VDC, 10 µA
Ambient temperature: -20 °C - +50 °C
 The specifications of BUL-8000(Z1) are as follows:
Pump circuit: Maximum voltage of 4.25 V, maximum current of 1.12 A andmaximum power of 901 mW
Infrared detection circuit : Maximum voltage of 4.25 V, maximum current of 0.768 A andmaximum power of 618 mW
Buzzer circuit: Maximum voltage of 4.25 V, maximum current of 0.410 A andmaximum power of 330 mW
Main circuit: Maximum voltage of 4.25 V, maximum current of 0.653 A andmaximum power of 526 mW
Battery charging contact : Maximum voltage of 250 VAC, 50/60 Hz
Ambient temperature: -20 °C - +50 °C
 The specifications of BUD-8000(Z) are as follows:
Pump circuit: Maximum voltage of 4.95 V, maximum current of 1.12 A andmaximum power of 1138 mW
Infrared detection circuit : Maximum voltage of 4.95 V, maximum current of 0.834 A andmaximum power of 853 mW
Buzzer circuit: Maximum voltage of 4.95 V, maximum current of 0.431 A andmaximum power of 441 mW
Main circuit: Maximum voltage of 4.95 V, maximum current of 0.717 A andmaximum power of 733 mW
Power supply: 4.5 V 150 mA (Type LR6 manufactured by Toshiba, 3 pcs)
Ambient temperature: -20 °C - +50 °C- 14 -

3. Product Components

3-1. Main unit and standard accessories

DANGER Make sure that the product model on the nameplate is correct.
Inappropriate combinations of models deviate from the range of explosion-proof certification.
 The nameplate shows the followings as well as the product model.
Product model : Main unit: RX-8500, 8700
Lithium ion battery unit: BUL-8000(Z1)Dry battery unit: BUD-8000 (Z)Explosion proof class : 【RX-8500,8700】Ex ia IIC T4X【BUL-8000(Z1), BUD-8000(Z)】 Ex ia IIC T4
Ambient temperature : -20 °C - +50 °C
Charging terminal rating : 【BUL-8000(Z1)】Allowable voltage 250 VAC, 50/60 Hz
Warnings : 【BUL-8000(Z1), BUD-8000(Z)】Inhibit to take off battery unit in non-hazardous area.
 Manufacturer : RIKEN KEIKI Co., Ltd.
 IP protection class: IP20

NOTE
Connect either the dry battery unit BUD-8000(Z) or
lithium ion battery unit BUL-8000(Z1).
Check the model of the battery unit with the nameplateaffixed to the unit.
A nameplate indicating a compatible model is affixed to thebattery unit to avoid using the gas monitor in combination
with a wrong unit.
Check this information and use a correct combination.

(Top view of battery unit)

Nameplate(Side view of battery unit)- 15 -

3. Product Components

3-2. Names and functions for each part3-2. Names and functions for each part
This section describes names and functions of main unit and battery unit parts and LCD display.

<RX-8500 (with lithium ion battery unit BUL-8000(Z1))><Main Unit>

Name

Main function(1)

LCD display

Displays a gas concentration, alarm, etc.

(2)

Buzzer sound opening

Emits a buzzer sound at an alarm. (Do not block it.)(3)

Alarm LED arrays (top)(4)

Alarm LED arrays (left)(5)

Alarm LED arrays(right)(6)

Infraredcommunication port

The red lamp blinks in response to an alarm.

Used to carry out data communications with a PC when the datalogger management program is used.

- 16 -

3. Product Components

3-2. Names and functions for each part

Name

Main function▲/AIR switch

Used to perform air calibration on the measurement screen. Or
used to increase a numeric value in the display/setting mode.

(8)▼/PUMP switch

Used to turn ON/OFF the pump on the measurement screen. Or
used to reset an alarm in an alarm state.
In the display/setting mode, press this switch to decrease a numericvalue.

(9)

PEAK/ESC switch

Used to switch the mode or display.

(10)

POWER/ENTER switch

Used to turn ON/OFF the power.

(11)

Gas outlet (GAS OUT)

Exhausts the gas drawn into the gas monitor. (Do not block it.)(12)

Gas inlet (GAS IN)

Draws a gas into the gas monitor. Connects the accessory tube, etc.

(13)

Charging indicator
lampLights up in red during charging and goes off when charging iscompleted.

(14)

Charging jack cover

Removed to connect an AC adapter and charge the batteries.

(15)

Buzzer sound opening

Emits a buzzer sound at an alarm. (Do not block it.)(16)

Battery unit screws

Turn these screws to detach and replace the battery unit.

(7)

CAUTION Do not jab the buzzer opening with a sharp-pointed item. The unit may malfunction or getdamaged, allowing water or foreign matter, etc. to get inside.
 Do not remove the panel sheet on the surface. The water-proof and dust-proof performances
will be deteriorated.
 Do not affix a label or the like on the infrared port. Infrared communications can no longer be
conducted.

- 17 -

3. Product Components

3-2. Names and functions for each part

<Display>

Item

Main function(1)

Operating status
display

Displays the operating status in the measuring mode.
A heart symbol blinks in the normal state.

(2)

Combustible gas
concentration display
Digital and bar display

Displays the gas concentration as a numeric value and a level in thebar graph.

(3)

Carbon monoxide
concentration display
Digital and bar display

Displays the gas concentration as a numeric value and a level in thebar graph.

(4)

Battery level icon

Displays the battery level. See NOTE for a guide for battery level.

(5)

Pump driving indicator

Displays the drawing status in the measuring mode. Rotates at a
normal state.

(6)

Oxygen concentration
display
Digital and bar display

Displays the gas concentration as a numeric value and a level in thebar graph.

(7)

Carbon dioxide
concentration display
Digital and bar display

Displays the gas concentration as a numeric value
and a level in the bar graph.

NOTE The meanings of battery level icons are as follows:: Sufficient/: Low/: Needs charging
If the battery level further drops, the inside of the battery icon starts to blink ( The gas alarm function is an optional setting.
 When [NO ALARM] lights up, no gas alarm pattern is performed.
[NO ALARM] display- 18 -).

3. Product Components

3-2. Names and functions for each part<RX-8700 (with lithium ion battery unit BUL-8000)><Main Unit>

Name

Main function(1)

LCD display

Displays a gas concentration, alarm, etc.

(2)

Buzzer sound opening

Emits a buzzer sound at an alarm. (Do not block it.)(3)

Alarm LED arrays

The red lamp blinks in response to an alarm.

(4)

HC/O2/H2S [lowconcentration]measuring modeindicator lamp

Lights up (in green) when HC/O2/H2S [low concentration] measuringmode is entered.

(5)

H2S [highconcentration]measuring modeindicator lamp

Lights up (in green) when H2S [high concentration] measuring modeis entered.

(6)

Infraredcommunication port

Used to carry out data communications with a PC when the datalogger management program is used.

(7)▲/AIR switch

Used to perform air calibration on the measurement screen. Or
used to increase a numeric value in the display/setting mode.

- 19 -

3. Product Components
Name
(8)

▼/PUMP switch

3-2. Names and functions for each part
Main function
Used to turn ON/OFF the pump on the measurement screen. Or
used to reset an alarm in an alarm state.
In the display/setting mode, press this switch to decrease a numericvalue.

(9)

PEAK/L/H/ESC switch

Used to switch the mode between the H2S [high concentration]measuring mode and HC/O2/H2S [low concentration] measuringmode on the measurement screen.
Or used to switch the mode or display in the display/setting mode.

(10)

POWER/ENTER switch

Used to turn ON/OFF the power.

(11)

Gas outlet (GAS OUT)

Exhausts the gas drawn into the gas monitor. (Do not block it.)(12)

Gas inlet (GAS IN)

Draws a gas into the gas monitor. Connects the accessory tube, etc.

(13)

Charging indicator
lampLights up in red during charging and goes off when charging iscompleted.

(14)

Charging jack cover

Removed to connect an AC adapter and charge the batteries.

(15)

Buzzer sound opening

Emits a buzzer sound at an alarm. (Do not block it.)(16)

Battery unit screws

Turn these screws to detach and replace the battery unit.

CAUTION Do not jab the buzzer opening with a sharp-pointed item. The unit may malfunction or getdamaged, allowing water or foreign matter, etc. to get inside.
 Do not remove the panel sheet on the surface. The water-proof and dust-proof performances
will be deteriorated.
 Do not affix a label or the like on the infrared port. Infrared communications can no longer be
conducted.

- 20 -

3. Product Components

3-2. Names and functions for each part

<Display (HC/O2/H2S [low concentration] measuring mode)>

Item

Main function(1)

Operating status
display

Displays the operating status in the measuring mode.
A heart symbol blinks in the normal state.

(2)

Combustible gas
concentration display
Digital and bar display

Displays the gas concentration as a numeric value and a level in thebar graph.
(HC concentration is displayed after isobutane conversion.)(3)

Hydrogen sulfide[low concentration]
concentration display
Digital and bar display

Displays the gas concentration as a numeric value and a level in thebar graph.

(4)

Battery level icon

Displays the battery level. See NOTE for a guide for battery level.

(5)

Pump driving indicator

Displays the drawing status in the measuring mode. Rotates at a
normal state.

(6)

Oxygen concentration
display
Digital and bar display

Displays the gas concentration as a numeric value and a level in thebar graph.

- 21 -

3. Product Components

3-2. Names and functions for each part

<Display (H2S [high concentration] measuring mode)>

Item

Main function(1)

Operating status
display

Displays the operating status in the measuring mode.
A heart symbol blinks in the normal state.

(2)

Battery level icon

Displays the battery level. See NOTE for a guide for battery level.

(3)

Pump driving indicator

Displays the drawing status in the measuring mode. Rotates at a
normal state.

(4)

Hydrogen sulfide [highDisplays the gas concentration as a numeric value and a level in theconcentration]
bar graph.
concentration display
Digital and bar display

NOTE

 The meanings of battery level icons are as follows:: Sufficient/: Low/: Needs charging
If the battery level further drops, the inside of the battery icon starts to blink ( The gas alarm function is an optional setting.
 When [NO ALARM] lights up, no gas alarm pattern is performed.
[NO ALARM] display- 22 -).

4. How to Use

4-1. Before using the gas monitor

44.

How to Use

4-1. Before using the gas monitor
Not only the first-time users but also the users who have already used the gas monitor must follow theoperating precautions.
Ignoring the precautions may damage the unit, resulting in inaccurate gas measurement.

4-2. Preparation for start-up
Before starting gas measurement, check the followings.
••••

Check that the battery level is sufficient.
Check that the filter inside the gas monitor is not contaminated or clogged.
Check that there is no bend or hole in the gas sampling hose and relay tube.
Check that the main unit, relay tube, filter tube, gas sampling hose and gas sampling probe areconnected properly in this order.

DANGER Perform charging of the lithium ion battery unit or replacement of the battery unit/dry batteries
in a safe place.

- 23 -

4. How to Use

4-2. Preparation for start-up

4-2-1. Charging the lithium ion battery unit (BUL-8000(Z1))
When the gas monitor is used for the first time, or when the battery level is low, be sure to use thededicated AC adapter to charge the battery unit.

1

Open the charging jackcover of the lithium ion
battery unit.

2

Insert the AC adapter plug
into the charging jack.

Charging indicator lamp
Insert the plug of AC
adapter for charging to
the charging jack.

Charging jackPlug

AC adapter for charging

3

Insert the AC adapter to theoutlet.
When charging is started, thecharging indicator lamp lights up in
red.
(Charging time: Three hours at the
maximum until the battery unit is fully
charged)When charging is completed, thecharging indicator lamp goes off.

4

When charging iscompleted, disconnect theAC adapter from the outlet.

5

Disconnect the AC adapter
plug from the charging jackand attach the charging
jack cover.
Push the charging jack cover as far
as it will go.

DANGER Charge the battery unit using the dedicated AC adapter in a safe place.
 Charge the battery unit at ambient temperatures between 0 - 40 ºC.
 Do not use the gas monitor while charging it. Correct measurements cannot be obtained.
Furthermore, the batteries get deteriorated more quickly and may have shorter life.
 The charger is neither water-proof nor dust-proof. Do not charge the batteries while the gas
monitor is wet.
 The charger is not explosion-proof.
- 24 -

4. How to Use

4-2. Preparation for start-up

CAUTION Do not pull the charging jack cover hard to open the cover in the step 1. It may get damaged.
 Do not use the battery unit with the charging jack cover detached. Dust or water may get into
the gas monitor, causing it to malfunction. If the charging jack cover is damaged, replace thebattery unit with new one.
 If the charging jack cover is not completely closed, water may get in from the charging jack.
The same thing may occur if a minute foreign substance gets stuck between the cover and theunit.
 Disconnect the AC adapter from the outlet while it is not in use.

NOTE

 During charging, the lithium ion battery unit may get hot, but this is not an abnormality.
 The temperature of the unit is high immediately after charging is completed. Let it stand for 10
minutes or more before using it. Using the lithium ion battery unit while it is still hot may cause
erroneous measurement.
 When a fully charged battery unit is recharged, the charging indicator lamp does not light up.

4-2-2. Detaching and attaching the battery unit
1

Loosen the two battery unit
screws on the bottom.

<Lithium ion battery>
Battery unit screws<Dry battery unit (option)>
Battery unit screws

2

Detach the battery unit.

- 25 -

4. How to Use

34-2. Preparation for start-up

Attach a new battery unit
and then tighten the twobattery unit screws.
Attach the battery unit in the correct
direction with attention to theconnection terminal or projections.

Connection
terminal

CAUTION Turn off the power of the gas monitor before replacing the battery unit.
 Replace the battery unit in a safe place.
 If the battery unit screws are not tightened securely, the battery unit may drop off or water may
get in through the clearance. Water may also get in if a minute foreign substance is caught
between the battery unit and gas monitor.
 Do not damage the rubber seal. To maintain the water-proof and dust-proof performances, it isrecommended to replace the rubber seal every two years, whether or not it has an abnormality.

4-2-3. Attaching batteries to the dry battery unit (BUD-8000(Z),option)When the gas monitor is used for the first time, or when the battery level is low, attach new AA alkaline
batteries.

1

Open the battery coverlocated at the bottom of thedry battery unit using aflathead screwdriver orcoin.

Battery coverBattery cover fixing screw

2

Attach three new drybatteries observing thecorrect polarity.

Indicationof battery
polarity

Remove old batteries as needed.

- 26 -

Batteries4. How to Use

34-2. Preparation for start-up

Close the battery cover andtighten the battery coverfixing screw.

DANGER The explosion-proof standard for the gas monitor requires the use of TOSHIBA dry batteries.
Use three Alkaline AA batteries, type LR6 manufactured by Toshiba to use the gas monitor as
an explosion-proof unit.

CAUTION
Replacement of batteries
 Turn off the power of the gas monitor before replacing the dry batteries.
 Replace the dry batteries in a safe place.
 Pay attention to the polarities of the dry batteries.
 If the battery cover fixing screw is not tightened securely, the dry batteries may drop off orwater may get in through the clearance. Water may also get in if a minute foreign substance iscaught between the cover and the unit.
Batteries Replace all of the three batteries with new ones.
 Rechargeable batteries cannot be used.

4-2-4. Connecting the gas sampling probe and gas sampling
hoses
Attach the gas sampling hose to the gas sampling probe.
Connect the relay tube, filter tube, gas sampling hose and gas sampling probe in this order securely to thegas inlet (GAS IN) of the main unit.

- 27 -

4. How to Use

4-2. Preparation for start-up

CAUTION Use only a gas sampling hose specified by RIKEN KEIKI.
 The gas sampling hose must be connected to the gas sampling probe before use so that no
foreign substance is drawn into it.
 Be sure to connect the gas sampling probe and gas sampling hose by fastening them by hand.
Fastening them too tight using a tool may break the plastic part of the gas sampling probe.

NOTE When connecting a part to the gas inlet (GAS IN), push the part until it clicks into place.

- 28 -

4. How to Use

4-3. How to start the gas monitor

4-3. How to start the gas monitor
When the power is turned on, self-diagnosis starts and then the measurement screen appears.

4-3-1. Power-on
Hold down the POWER/ENTER switch (over three seconds) until the buzzer blips to turn on the power.
When the power is turned on, the LCD display changes automatically as shown below before themeasurement screen is displayed.

1

Hold down the
POWER/ENTER switch
for at least 3 seconds.

Hold down theswitch until theentire LCD
display andalarm lamp lightup and thebuzzer blips.

RX-8500 LCD display

RX-8700 LCD display

▼

▼

▼

▼

▼

▼

▼

▼

All LCDs lightup

Date/time
display

Battery voltage
display

Pump warm-up- 29 -

4. How to Use

4-3. How to start the gas monitor

Gas name
display

▼

▼

▼

▼

▼

▼

▲
▼

▲
▼

▼

▼

Full scale
display

ID display

The screens on
the right are
displayedalternately until
the ENTER
switch ispressed.

2

Filterconnection
check

Press the ENTER switch.
The sensor warm-up operation is
performed for about 25 seconds.

The buzzer blips twice and thenthe measurement screen isdisplayed.

- 30 -

4. How to Use

4-3. How to start the gas monitor

CAUTION After start-up, perform air calibration (P. 37) before performing gas measurement.
 RX-8700 is started in the H2S [high concentration] measuring mode.

NOTE If any abnormality is detected in the sensor, a sensor abnormality
alarm is triggered just before entering the measuring mode.
Press the ▼ switch when a sensor abnormality alarm is triggered.
The sensor abnormality alarm is reset temporarily, and [- - -]appears in the concentration display area of the gas with sensor
abnormality before starting measurement (the alarm cannot be

reset if all sensors have an abnormality).
In this case, promptly contact RIKEN KEIKI. Gas measurement
cannot be performed with a sensor having an abnormality.
 If there is an abnormality in the built-in clock, a fault alarm [FAIL
CLOCK] may be triggered. Press the ▼ switch when the alarm istriggered. The fault alarm is temporarily reset, and measurement isstarted with incorrect clock time.

Display example(Oxygen sensor abnormality)

4-3-2. Switching the hydrogen sulfide measuring mode range
on RX-8700
RX-8700 switches the mode between the H2S [high concentration] measuring mode and HC/O2/H2S [lowconcentration] measuring mode.

Hold down the L/H
switch (about one
second) and release it
when the buzzer blips
once.
H2S [high concentration]measuring mode

- 31 -

HC/O2/H2S[low concentration]measuring mode4. How to Use

4-4. Basic operating procedures

4-4. Basic operating proceduresThis mode is used on the measurement screen after power-on.

4-4-1. RX-8500 basic operating procedures<Measurement screen>Long pressing<Fault alarm state (self-latching)>(Low flow rate)<Air calibration mode>

Pressing
at thesame
time

Pressing at
the same time

<Manual memory mode><Calibration mode>Long pressing

Short pressing<Pump ON/OFF mode><Display/setting mode>- 32 -

4. How to Use

4-4. Basic operating procedures

4-4-2. RX-8700 basic operating proceduresLong
pressing(about1 second)

HC/O2/H2S <low concentration>measuring mode

H2S <high concentration>measuring mode

<Measurement screen>(HC/O2/H2S <low concentration>measuring mode)Long pressing<Fault alarm state (self-latching)>(Low flow rate)<Air calibration mode>

Pressing
at thesame
time

Pressing at
the same time<Calibration mode><Manual memory mode>Long pressing<Pump ON/OFF mode>Long
pressing(about3 seconds)<Display/setting mode>- 33 -

4. How to Use

4-5. Measurement

4-5. Measurement
Measure gas concentration on the measurement screen. Put the gas sampling probe close to themeasurement area.
Once gas concentration measurement is started, the gas monitor draws in a measuring gas for a certain
period of time and then displays a concentration value as a measurement result.

4-5-1. Gas concentration measurement
With the measurement screen displayed, put the gas sampling probe close to the measurement area andtake the reading on the LCD display.

<RX-8500>

Combustible gas
concentration(CH4: Methane): 0.0 %LEL, 0 vol%Carbon monoxide
concentration: 0 ppm

Oxygen concentration: 20.9 %Carbon dioxide
concentration: 0.00 vol%Battery level: Sufficient<RX-8700>
H2S [highconcentration]measuring mode
Hydrogen sulfide
concentration: 0 ppm

HC/O2/H2S [lowconcentration]measuring mode

Combustible gas
concentration(HC: Isobutane
converted): 0.0 %LEL, 0 vol%Oxygen concentration: 20.9 %Hydrogen sulfide
concentration: 0.0 ppm
Battery level: Sufficient- 34 -

4. How to Use

4-5. Measurement

DANGERWARNING WhileThe gasconducting
monitor ismeasurement
designed to draw
in a manhole
gases aroundor confined
it underspace,
the atmospheric
do not lean pressure.
over or look
If intothe manhole
excessivepressureor closed
is applied
space. to
It maythe gasleadinlet
to dangers(GAS IN)
becauseand outlet
oxygen-deficient(GAS OUT) ofair
the
orgas
other
gases may
monitor,measured
blow out.
gases may leak out from its inside and may cause dangerous conditions.
sure that excessive
is notappliedto them while
used.
 Be
Oxygen-deficient
air or pressureother gases
may
be discharged
from thegas exhausting outlet of the Dogasnotmonitor.
connect
Never
the sampling
inhale thehose
air ordirectlygases.to a measurement area with a pressure higher thanatmospheric pressure.
The internal
pipingsystemmay
be damaged.
 theHigh-concentration(100 %LEL
or higher)
gases
may bedischarged
from the gas exhausting Whenairthecalibrationis performedin thecheck the atmosphere for freshness
outlet ofgas monitor.
Never usefire atmosphere,
near it.
before measuring
beginning it.
interference
gases exist,
cannot be
theIf oxygen
concentration,
do thenot calibration
measure anything
butperformeda mixture properly,of air and Whenthus leading to dangers when the gas leaks.
 Issuance of a gas alarm indicates that there are extreme dangers. Take proper actions basedon your judgment.
 Before use, check that there remains sufficient battery power. When the gas monitor is used forthe first time or is not used for a long period, the batteries may be exhausted. Either fully
charge the batteries or replace them with new ones before use.
 Gas measurement cannot be performed with a low battery voltage. If the low battery voltage
alarm is triggered during use, turn off the power and promptly charge or replace the batteries ina safe place.
 Do not block the buzzer sound opening. No alarm sound can be heard.

CAUTION Before performing gas measurement, connect the gas sampling probe provided with the gas
monitor to prevent disturbances by air dust.
 When measuring concentrations of oxygen in inert gases for a long time, the carbon dioxide
concentration in the air must be 15 % or less. When the gas monitor is used in the inert gas
with a carbon dioxide concentration higher than 15 %, perform measurement in as short time
as possible.
 Do not use the gas monitor in a place with high oxygen concentration for a long time. The
oxygen sensor life may be shortened.

NOTE In a low-temperature environment, the operating time is shortened due to the battery performance
property.
 At low temperatures, the responses of the LCD display may slow down.
 If a combustible gas with 100 %LEL or higher concentration is drawn, adsorbed gases may remain in
the gas sampling hose or gas sampling probe. After drawing a high-concentration combustible gas,
be sure to draw fresh air and perform air cleaning until the reading nears zero to remove adsorbed
gases. Performing air calibration before cleaning completely may result in inaccurate air calibration,
giving adverse influence on measurement. In such a case, remove the gas sampling probe and hoseand then perform air calibration to avoid inaccurate calibration.
 [RX-8700] To measure an area where high-concentration hydrogen sulfide may be present, use theH2S [high concentration] measuring mode.
 [RX-8700] To measure hydrogen sulfide concentration, check that hydrogen sulfide concentration isless than 100 ppm in the H2S [high concentration] measuring mode and then measure combustible
gas and oxygen concentrations in the HC/O2/H2S [low concentration] measuring mode. Drawing
high-concentration hydrogen sulfide in the HC/O2/H2S [low concentration] measuring mode may
damage the combustible gas, oxygen or low-concentration hydrogen sulfide sensor.

- 35 -

4. How to Use

4-5. Measurement

4-5-2. Range switching point
The display automatically switches to the vol% range when the concentration of a measured combustible
gas exceeds 100 %LEL. When the concentration drops, the display returns to the %LEL range again. The
following shows an example of switching timing.

<Example of gas concentrations and range switching timing>(1) RX-8500
CH4 concentration

100 %LEL(5.0 vol%)%LEL range

vol% range

Switching point%LEL range

Switching point

Combustible gas concentration display•
CH4: Methane•
The range switching point is a lower explosive limit of a gas. It is 5.0 vol% for methane.
(2) RX-8700
HC concentration

100 %LEL(1.8 vol%)%LEL range

vol% range

Switching point%LEL range

Switching point

Combustible gas concentration display•
HC: Isobutane converted•
The range switching point is a lower explosive limit of a gas. It is 1.8 vol% for isobutane.

- 36 -

4. How to Use

4-6. Air calibration

4-6. Air calibration
Air calibration is zero adjustment to correctly measure the current gas concentration.

4-6-1. Attaching the CO2 removal filter (RX-8500)
To perform zero calibration for carbon dioxide (CO2), CO2 in the air needs to be removed using the CO2
removal filter.
Attach the CO2 removal filter so that the arrow (->) on the side is directed at the filter tube.

Filter tube side
Direct the arrow at the filter tube.

Stand the CO2 removal filter to use. With it laid horizontally, CO2 in the air may not be absorbed.
Correct use

Incorrect use

With the CO2 removal filter laid horizontally, air
passes through the shaded area and CO2
cannot be absorbed.

CO2 removal filter
Stand the CO2
removal filter to use.

Filter tube
CO2 removal filter

Filter tube

The number of usable times per filter depends on the carbon dioxide concentration in the air. It varies also
by the air tightness of CO2 removal filter, storage temperature or humidity.
The following table shows guide values assuming that each use takes one minute for drawing. However,
use the removal filter with a margin when the carbon dioxide concentration in the environment is unknown.
Measurement
environment
carbon dioxide (CO2)concentration
500 ppm1000 ppm
2000 ppm
4000 ppm

Estimated number of usable times
in consideration of storage
condition
Approx. 1000 times
Approx. 500 times
Approx. 200 times
Approx. 100 times- 37 -

4. How to Use

4-6. Air calibration

CAUTION Do not draw high-concentration carbon dioxide during zero calibration.
 Do not breathe on the inlet during zero calibration.
 Block ventilation to the air after using the CO2 removal filter. With the air mixed, the absorbent
absorbs carbon dioxide in the air, resulting in degraded absorption performance.
 Store the CO2 removal filter in a dry place away from direct sunlight.

NOTE

 The number of usable times per filter depends on the carbon dioxide concentration in the air. It varies
also by the air tightness of CO2 removal filter, storage temperature or humidity.
 The above table shows guide values assuming that each use takes one minute for drawing. However,
use the removal filter with a margin when the carbon dioxide concentration in the environment is
unknown.

4-6-2. Air calibration procedure1RX-8500 LCD display

RX-8700 LCD display

▼

▼

▼

▼

Hold down the AIR switch
on the measurement
screen.
The air calibration screen isdisplayed.

Keep the AIR switch pressed while
the screen shown in the right figure
is displayed.
Air calibration is not started if theswitch is released before the screen
is displayed.
Press the ESC switch to stop air
calibration.

- 38 -

4. How to Use

2

4-6. Air calibration

Release the AIR switch
when the screen shown in
the right figure isdisplayed.
On RX-8500, nitrogen gas
calibration is performed next.
Pressing the ESC switch skips
nitrogen gas calibration andperforms air calibration.
On RX-8700, nitrogen gas
calibration is not performed.

3

For RX-8500, attach theCO2 removal filter andpress the ENTER switch.
See '4-6-1. Attaching the CO2
removal filter' for how to attach theCO2 removal filter.
▼

▼
▼
▼
▼
▼
▼
▼

When air calibration is completed,the screen shown in the right figure
is displayed.

WARNING When air calibration is performed in the atmosphere, check the atmosphere for freshness
before beginning it. If interference gases exist, air calibration cannot be performed, thus
leading to dangers when the gas leaks.
 Perform air calibration under pressure and temperature/humidity conditions close to those in
the operating environment and in fresh air.
 Perform air calibration after the reading is stabilized.
 If there is a sudden temperature change of 15 ºC or more between the storage and operational
locations, turn on the power of the gas monitor, let it stand for about 10 minutes in a similar
environment to the operational location, and perform air calibration in fresh air before using it.
 [RX-8500] The amount of carbon dioxide in the air is about 300 - 500 ppm. If air calibration forthe carbon dioxide sensor is performed while directly drawing air where carbon dioxide ispresent, correct measurement of gas concentration becomes impossible. Before performing air
calibration on RX-8500, attach the CO2 removal filter and draw air for at least one minute.

- 39 -

4. How to Use

4-6. Air calibration

NOTE If air calibration fails, [FAIL - AIR CAL] is displayed along with thename of gas sensor which has become faulty. Press the ▼ switch
to reset the fault alarm (calibration failure). When the alarm is reset,
the value before calibration is displayed.
 [RX-8500] Do not draw high-concentration carbon dioxide during air
calibration.
 [RX-8500] Do not breathe on the inlet (GAS IN) during air
Air calibration failure display example
calibration.
Oxygen (O2) sensor
 [RX-8500] Block ventilation to the air after using the carbon dioxide
removal filter. With the air mixed, the absorbent absorbs carbon dioxide in the air, resulting indegraded absorption performance.
 [RX-8700] Perform air calibration in each of the two modes (H2S [high concentration] measuringmode and HC/O2/H2S [low concentration] measuring mode).

- 40 -

4. How to Use

4-7. Manual memory

4-7. Manual memory
Up to 256 arbitrary instantaneous values during measurement can be recorded.
When the number of recorded data points reaches the maximum, recorded data will be overwritten, startingfrom the oldest data.

1

Hold down the ▲ and PEAK switches on themeasurement screen.
The memory number, recorded date and recorded concentration
are displayed in turn as shown below.
Display example (RX-8500)

Memory No.

Recorded date

Recorded concentration

Press the ESC switch to skip recording the displayed contents. The
measurement screen returns.

2

Press the ENTER switch.
[END] is displayed on the screen, and the memory number, dateand gas concentration at the time the ENTER switch is pressed arerecorded.
After recording the data, the measurement screen returns
automatically.

NOTE If PEAK and ▲ switches are not pressed at the same time, the air calibration (P. 37) ordisplay/setting (P. 44) screen is displayed. In this case, release both switches and try again after
displaying the measurement screen.

- 41 -

4. How to Use

4-8. Stopping the pump (PUMP OFF mode)

4-8. Stopping the pump (PUMP OFF mode)
The pump operation can be stopped.

1

Hold down the PUMP switch on the measurement
screen (about five seconds).
The pump stops operating.
The buzzer blips twice every three minutes or so while the pump
operation is stopped.

2

Press the PUMP switch to activate the pump.
The measurement screen returns.

WARNING No alarm is triggered under any circumstances in the PUMP OFF state.
 The measuring mode does not return automatically in the PUMP OFF state.

- 42 -

4. How to Use

4-9. Power-off

4-9. Power-off
CAUTION If the concentration display is not reset to zero (or 20.9 % for the oxygen concentration display)after measurement is completed, leave the gas monitor in fresh air until the display returns tozero and then turn off the power.

Keep the POWER/ENTER switch pressed.
To turn off the power, hold down the POWER/ENTER switch
after the display returns to zero (0, or 20.9 % for oxygen) in asafe place.
The buzzer blips three times and [TURN OFF] appears on thedisplay before the power is turned off.

Power-offNOTE To turn off the power, keep the switch pressed until the display disappears.
 If the display is not zero when the power is turned off, a purge operation may be performed for 30
seconds at the maximum on RX-8500 or 60 seconds at the maximum on RX-8700 to clean the insideof the gas monitor.

<RX-8500><RX-8700>
A purge operation is performed in the H2S [high concentration]measuring mode (HI) and then the HC/O2/H2S [low concentration]measuring mode (LO).

- 43 -

5. Setting Procedure

5-1. Display/setting mode

5
5.

Setting Procedure

5-1. Display/setting modeThis mode allows users to display or change various settings.

RX-8500
1

RX-8700

Press the PEAK switch on themeasurement screen.
The following display/setting screens are
displayed in turn by pressing the PEAK
switch.
･ Press PEAK once: PEAK display/clear･ Press PEAK twice: Alarm setpoint
display･ Press PEAK three times: Clock display･ Press PEAK four times: Station ID
display･ Press PEAK five times: Log data
display･ Press PEAK six times: Return to themeasurement screen

1

Hold down the PEAK switch on
the measurement screen (about
three seconds).

2

Release the switch when thebuzzer blips twice.
･ Hold down PEAK: PEAK display/clear

3

Press the PEAK switch again.
The following display/setting screens are
displayed in turn by pressing the PEAK
switch.
･ Hold down PEAK and then press it
once: Alarm setpoint display･ Hold down PEAK and then press it
twice: Clock display･ Hold down PEAK and then press it threetimes: Station ID display･ Hold down PEAK and then press it fourtimes: Log data display･ Hold down PEAK and then press it fivetimes: Return to the measurement
screenNOTE When the unoperated period lasts about 20 seconds, the measurement screen returns automatically.
 [RX-8700] When the switch is released after the buzzer blips once in the step 2, it causes a switch
between the H2S [high concentration] measuring mode and HC/O2/H2S [low concentration]measuring mode and fails to enter the display/setting mode.
 [RX-8700] The display/setting mode can be entered from either of the two modes (H2S [highconcentration] measuring mode and HC/O2/H2S [low concentration] measuring mode).

- 44 -

5. Setting Procedure

Item
PEAK display/clear

5-1. Display/setting mode

Details

LCD display

Displays the maximum
concentration (or minimum
concentration for oxygen)obtained during
measurement frompower-on to the present.
Clears a peak value as
well.

PEAK display on RX-8500

Remarks
Go to thedisplay/clear
screen(P. 46)

Alarm setpoint display(Full scale/alarm
setpoint display/gas
alarm test)

Displays the full scalevalue and first and second
alarm setpoints, andallows users to check
alarm activation.
* The gas alarm function
is an optional function.

Clock display

Displays the current date
and time.

Station ID display

Displays station IDs
registered in advance.
ID selection is alsoavailable.

Press theENTER switch
to go to thedisplay/selection
screen(P. 48)Log data display

Displays data recorded in
the manual memory.

Press theENTER switch
to go to thedisplay screen(P. 49)- 45 -

Press theENTER switch
to go to thedisplay screen(P. 47)

5. Setting Procedure

5-2. PEAK display/clear

5-2. PEAK display/clear
This item displays or clears the maximum concentration (or minimum concentration for oxygen) obtained
during measurement from power-on to the present.

1

Display the screen shown in the right figure oneach model.
RX-8500

RX-8700

Press the PEAK switch once
on the measurement screen.

Hold down the PEAK switch on
the measurement screen(about three seconds).

2

Hold down the ▼ switch to clear PEAK value.

3

Release the ▼ switch when [RELEASE] isdisplayed.

PEAK display on RX-8500

PEAK value has been cleared.
After clearing the value, the buzzer blips and the screen in the step
1 returns.

NOTE When the unoperated period lasts about 20 seconds, the screen in the step 1 is replaced with themeasurement screen.

- 46 -

5. Setting Procedure

5-3. Full scale/alarm setpoint display/gas alarm test (optional function)

5-3. Full scale/alarm setpoint display/gas alarm test
(optional function)
This item displays the full scale value and first and second alarm setpoints, and allows users to check
alarm activation.
Normally the gas alarm function is set to OFF and unavailable (optional function). To use this function,please contact RIKEN KEIKI.

1

Display the screen shown in the right figure oneach model.
[ALARM-P] and [YES/ENT] are displayed alternately in the lower
part of the screen.

RX-8500

RX-8700

Press the PEAK switch twiceon the measurement screen.

•

•

▲
▼

Hold down the PEAK
switch on themeasurement screen(about three seconds).
Press the PEAK switch
once.

2

Press the ENTER switch.

3

Press the ▲/▼ switch to display the full scale or
first/second alarm setpoint value.
Display example of the case without alarm setpoints on RX-8500

4Full scale valueFirst alarm setpoint

Second alarm setpoint

The OVER alarm (over scale)activation occurs in an alarm
test.

[OFF] appears in theconcentration display area.

[OFF] appears in theconcentration display area.

Display a desired screen and press the ENTER
switch.
The alarm LED arrays blink in red, allowing the user to check thealarm activation of the screen displayed.

5

Press the ENTER or ESC switch to stop the alarm
activation.
Pressing the ENTER switch stops the alarm activation.
Pressing the ESC switch stops the alarm activation and then returns
to the screen in the step 1.

- 47 -

5. Setting Procedure

5-4. Station ID display

NOTE When the unoperated period lasts about 20 seconds, the screen in the step 1 is replaced with themeasurement screen.
 No display switch is made during alarm test.

5-4. Station ID display
This item displays the registered station IDs and allows users to make a selection.

1

Display the screen shown in the right figure oneach model.
RX-8500

RX-8700

Press the PEAK switch fourtimes on the measurement
screen.

••Hold down the PEAK
switch on the measurement
screen(about three seconds).
Press the PEAK switch
three times.

2

Press the ENTER switch.

3

Select station ID with the ▲/▼ switch.
When an ID change is not necessary, press the ESC switch.

4

Press the ENTER switch.
When the ID display is finished, the buzzer blips and the screen in
the step 1 returns.

NOTE When the unoperated period lasts about 20 seconds, the screen in thestep 1 is replaced with the measurement screen.
 When the unit is used for the first time, station ID is displayed asshown in the right figure.
 On the gas monitor, IDs from ST-ID000 to ST-ID127 have beenregistered, unless otherwise specified.
 The data logger management program (optional) is required to registeror change an ID.
Please contact RIKEN KEIKI for more information.

- 48 -

5. Setting Procedure

5-5. Log data display

5-5. Log data display
This item displays the gas concentration data recorded in the manual memory.

1

Display the screen shown in the right figure oneach model.
RX-8500

RX-8700

Press the PEAK switch fourtimes on the measurement
screen.

••Hold down the PEAK
switch on the measurement
screen(about three seconds).
Press the PEAK switch
three times.

2

Press the ENTER switch.

3

Select log data with the ▲/▼ switch and thenpress the ENTER switch.
The concentration value of the selected log data is displayed.
Press the ESC switch to return to the screen in the step 1.

4

Press the ENTER switch.

Display example on

When the log data display is finished, the buzzer blips and theRX-8500

screen in the step 2 returns.

NOTE When the unoperated period lasts about 20 seconds, the screen in the step 1 or 3 is replaced withthe measurement screen.

- 49 -

6. Fault Alarm Function

Fault alarm activation

6
6.

Fault Alarm Function

Fault alarm activation"Fault alarm" is triggered when an abnormality is detected in the gas monitor. (Self-latching)In response to a fault alarm, the buzzer sounds and alarm LED arrays blink.
• Sounding buzzer: Repeatedly sounds intermittent beeps at about one-second intervals. "Beep-beep,
beep-beep"• Blinking alarm LED arrays: Repeatedly blinks at about one-second intervals.
<Fault alarm activation on RX-8500>
The alarm LED arrays on the top, left and right blink.

<Fault alarm activation on RX-8700>
Only the alarm LED arrays on the top blink.

Beep-beep,
beep-beep

Beep-beep,
beep-beep

There are following alarm types: low flow rate, battery voltage abnormalities, calibration failure, sensor
abnormalities, system abnormalities and clock abnormalities.
The following shows display examples of fault alarms.

(RX-8500)(RX-8700: Measuring H2S)

(RX-8700: Measuringlow-concentration hydrogen sulfide)

Low flow rate

Battery voltage abnormalities

Calibration failure- 50 -

Sensor abnormalities

6. Fault Alarm Function

System abnormalities

Fault alarm activation

Clock abnormalities

If a fault alarm is triggered, determine the cause and take appropriate action.
If the gas monitor has problems and is repeatedly malfunctioning, contact RIKEN KEIKI immediately.

NOTE

 For information on malfunctions (error messages), see 'Troubleshooting' (P. 64).

- 51 -

7. Maintenance7-1. Maintenance intervals and items

7
7.

Maintenance

The gas monitor is an important instrument for the purpose of safety.
To maintain the performance of the gas monitor and improve the reliability of safety, perform a regular
maintenance.

7-1. Maintenance intervals and items
Perform the following maintenance regularly before use.
••

Daily maintenance: Perform maintenance before beginning to work.
Regular maintenance: Perform maintenance once or more for every six months to maintain theperformance as a safety unit.
Maintenance
item

Maintenance content

Daily
maintenanceRegularmaintenanceBattery level

Check that the battery level is sufficient.

○○

Concentration
display check

Make the gas monitor draw in fresh air. Check thatthe concentration display value is zero (0, or 20.9
vol% for the oxygen concentration display). If it is notzero (0, or 20.9 vol% for the oxygen concentration
display), perform air calibration.

○○

Flow rate
check

Check the flow rate indicator for abnormalities.

○○

Filter check

Check the dust filter for dust or clogging.

○

○

Span
adjustment

Perform span adjustment using a calibration gas.

―○

WARNING If any abnormality is found in the gas monitor, promptly contact RIKEN KEIKI.

NOTE

 Perform span adjustment using a calibration gas at least once every six months.
 The span adjustment requires dedicated equipment and creation of calibration gas. Therefore,
contact RIKEN KEIKI for span adjustment.
 The built-in sensors of the gas monitor have a validity period and must be replaced regularly.
 The sensor life has expired if, for example, the sensors cannot be calibrated in span adjustment, thereadings do not come back after air calibration, or the readings fluctuate. In this case, contact RIKEN
KEIKI. Note that the warranty period is one year.

- 52 -

7. Maintenance7-1. Maintenance intervals and items

About maintenance services
We provide services on regular maintenance including span adjustment, other adjustments andmaintenance.
To make the calibration gas, dedicated tools, such as a gas cylinder of the specified concentration and gas
sampling bag, must be used.
Our qualified service engineers have expertise and knowledge on the dedicated tools used for services,along with other products. To maintain the safety operation of the gas monitor, please use our maintenanceservice.
The followings are typical maintenance services. Contact RIKEN KEIKI for more information.

<Main services>
Item
Details
Battery level
Checks the battery level.
check
Verifies that the concentration display value is zero (0, or 20.9 vol% for the oxygen
Concentration
concentration display) using a zero gas.
display check
Performs air calibration if the reading is incorrect.
Flow rate check

Checks the flow rate using an external flow meter.

Filter check

Checks the dust filter for dust or clogging.
Replaces a dirty or clogged dust filter.

Spanadjustment

Performs span adjustment using a calibration gas.

Cleaning andrepair of the unit
(visualdiagnosis)

Checks dust or damage on the surface of the unit, cleans and repairs such parts.
Replaces parts which are cracked or damaged.

Unit operation
check

Operates the switches to check the operation of functions and parameters, etc.

Replacement ofconsumableparts

Replaces consumable parts, such as a sensor, filter and pump.

- 53 -

7. Maintenance7-2. Span adjustment

7-2. Span adjustment
Perform span adjustment of sensors using a calibration gas more than once every six months.

7-2-1. Preparation
The zero and span adjustment requires dedicated equipment and a calibration gas. Please contact RIKEN
KEIKI .

<Required Equipment/Material>
Calibration gas (optional)
Gas sampling bag (optional)

7-2-2. How to connect
Connect the devices as shown below to perform span adjustment.
Gas samplingprobe(with a tube)
Gas
samplingbag

Gas outlet(GAS OUT)

Gas inlet(GAS IN)WARNING
Do not apply pressure to the gas sampling bag after attaching it. It may cause a calibration gas
to leak inside and result in a calibration failure.
Calibration gas
A calibration gas uses a hazardous gas (combustible gas, toxic gas, oxygen deficiency, etc.).
Handle the gas and related jigs and tools with careful attention to the followings.
Gas sampling bag
Use different gas sampling bags for each gas type and concentration to perform accurate
calibration.
Place for span adjustment
Do not perform calibration in a confined space.
Perform span adjustment in a place where no silicone, spray can gases, etc. is used.
Perform calibration indoors at normal temperatures without remarkable fluctuation (within±5 ºC).
A calibration gas uses a hazardous gas (combustible gas, toxic gas, oxygen deficiency, etc.).
Therefore, be sure to perform calibration in an exhaust booth or collect the calibration gas in an
exhaust bag.

CAUTION
Do not use a lighter gas to check the sensitivity of the gas monitor. A constituent of the lighter
gas may deteriorate the sensor performances.

- 54 -

7. Maintenance7-2. Span adjustment

7-2-3. Span adjustment procedure
Perform the span adjustment using the procedure shown below.

1

Prepare an optional calibration gas and set of gas
sampling bags.

2

Check that the relay tube, filter tube, gas sampling
hose and gas sampling probe are connected to thegas inlet (GAS IN) of the gas monitor.

3

Check that themeasurement screen isdisplayed on the gas
monitor.

4

Perform air calibration.

Measurement screen on
RX-8500

Measurement screen on
RX-8700

See '4-6. Air calibration'. (P. 37)
For RX-8700, perform air calibration in each of the two modes (H2S
[high concentration] measuring mode and HC/O2/H2S [lowconcentration] measuring mode).

5

Collect a calibration gas in each gas samplingbag.

6

Hold down the ▲ and ▼ switches at the same timeon the measurement screen (over one second).
The gas monitor enters the calibration mode.

7

Select the gas type to be calibrated with the ▲/▼switch.
Pressing the ENTER switch while [ESCAPE] is displayed returns to
the measurement screen.

<Calibration mode display on RX-8500>

CH4 %LEL adjustment

CH4 vol% adjustment

O2 % adjustment

CO ppm adjustment

CO2 vol% adjustment- 55 -

7. Maintenance7-2. Span adjustment<Calibration mode display on RX-8700>

HC %LEL adjustment

8

HC vol% adjustment

O2 % adjustment

H2S ppm adjustment<low concentration>

H2S ppm adjustment<high concentration>

Press the ENTER switch when the screen isdisplayed.
The concentration display blinks to indicate that calibration is ready.

9

Connect the gas sampling bag containing thecalibration gas which is the same as the selected
gas type to the gas sampling probe connected to
the gas monitor. Then introduce the gas into thegas monitor.
Wait until the concentration display is stabilized.

10

When the concentration display is stabilized,
adjust it to the calibration gas concentration
using the ▲/▼ switch.

▲▼

Display example on
RX-8500(Methane (CH4) %LEL
calibration)

11

Press the ENTER switch.
[END] appears when the calibration has finished.

- 56 -

7. Maintenance7-2. Span adjustment

12

Perform calibration for other gas types in thesame manner.

13

Return to the measurement screen whencalibration for all gas types has finished.
The measurement screen does not return automatically in thecalibration mode.
To return to the measurement screen from the calibration mode,press the ▲/▼ switch, select [ESCAPE] and then press the ENTER
switch.

WARNING Return to the measurement screen when calibration has finished. The measurement screen
does not return automatically in the calibration mode.

NOTE If the ▲ and ▼ switches are not pressed at the same time, the air calibration (P. 37) screen isdisplayed. In this case, release both switches and try again.
 While calibration is in process, press the ESC switch to stop the process. The measurement screen
returns.

- 57 -

7. Maintenance7-3. How to clean

7-3. How to clean
Clean the gas monitor if it becomes extremely dirty. The gas monitor must be turned off while cleaning it.
Use a waste cloth or the like to remove dust. Do not use water or organic solvent for cleaning because they
may cause malfunctions.
If the inside of the gas sampling hose is extremely contaminated, clean it with dry air, etc. to avoid adverse
influence on gas measurement.

CAUTION When cleaning the gas monitor, do not splash water over it or use organic solvents such as
alcohol and benzine on it. Otherwise, it may cause discoloration or damage to the surface ofthe gas monitor or a sensor failure.

NOTE When the gas monitor gets wet, water may remain in the buzzer sound opening or grooves. Drain
water as follows:(1) Wipe away moisture on the gas monitor thoroughly using a dry towel, cloth, etc.
(2) While holding the gas monitor firmly, shake it about ten times with the buzzer sound opening
facing downward.
(3) Wipe away moisture coming out from the inside thoroughly using a towel, cloth, etc.
(4) Place the gas monitor on a dry towel, cloth, etc. and let it stand at normal temperatures.

- 58 -

7. Maintenance7-4. Parts replacement

7-4. Parts replacement
7-4-1. Sensor replacement
The built-in sensors of the gas monitor must be replaced regularly.
See the regular replacement parts (P. 61) for recommended replacement intervals.
The sensor life has expired if, for example, the sensors cannot be adjusted in calibration, the readings do
not come back after air calibration, or the readings fluctuate.
In this case, contact RIKEN KEIKI.

7-4-2. Replacement procedure for gas sampling probe dust
filter
The gas sampling probe has a built-in dust filter.
Because the dust filter may gradually get dirty or clogged over time, it must be replaced regularly according
to the operating conditions.
It must be replaced especially when it shows a sign of water absorption, low flow rate or contamination.

1

Rotate the end of the probe
counterclockwise and removeit.
A round dust filter is contained here.
Check it for contamination or clogging.
Replace the dust filter if it is contaminatedheavily or clogged.

2

Take out the filter and replace itwith new one.

3

Reattach the filter case.

NOTE Use only the filters specified by RIKEN KEIKI.
 The dust filter of the gas sampling probe is different from that of the filter tube. Use the specified filter
for each part.
 See the regular replacement parts (P. 61) for a replacement filter.

- 59 -

7. Maintenance7-4. Parts replacement

7-4-3. Replacement procedure for filter tube dust filter
1

Loosen the cap (black) and removeit.

Cap (black)

Joint

2

3

As shown in the right figure, takeout the dust filter from the cap(black) and replace it with newone.

O-ring (S14)
Filter* The mesh sideshould face theO-ring (S14).

Reattach the cap (black).
Cap (black)

NOTE Use only the filters specified by RIKEN KEIKI.
 The dust filter of the gas sampling probe is different from that of the filter tube. Use the specified filter
for each part.
 See the regular replacement parts (P. 61) for a replacement filter.

7-4-4. Replacement procedure for filter tube absorbent cotton
1

Cut an absorbent cotton to thesize shown in the right figure(about 1.3 g) and round it into ashape.

Absorbent
cotton5 - 10 mm

70 ±3 mm

85 - 90 mm

2

Loosen the cap and remove it.

3

Replace the absorbent cotton.

Cap (black)Put the absorbent cotton into the pipe without
a gap between the pipe and cotton.

4

Pipe

Reattach the cap (black).

- 60 -

Absorbent
cotton7. Maintenance7-4. Parts replacement

7-4-5. Replacement of regular replacement parts
Replace the regular replacement parts of the gas monitor according to the recommended intervals.

<List of Recommended Regular Replacement Parts>
Item

Maintenanceintervals

Replacement
intervals
6 months 1 year
6 months 1 year
6 months 1 year
6 months 1 year

Quantity

Internal filter

6 months

1 pc

Dust filter (10 pcs for gas samplingprobe)

6 months

Dust filter (10 pcs for filter tube)

6 months

Absorbent cotton (25 g for filter
tube)

6 months

CO2 removal filter

6 months

1 year

1 pc

1 pc
1 pc
1.3 g

Remarks*
Part number 4181 5452
30Part number 4777 9022
50Part number 1879 0011
10RX-8500 onlyPart number 0913 0028
30

Combustible gas (CH4)/
carbon dioxide (CO2) sensor
Carbon monoxide (CO) sensor

6 months

5 years

1 pc

RX-8500 only*

6 months

1 year1 pc

Oxygen (O2) sensor

6 months

1 year

1 pc

Combustible gas (HC) sensor
Hydrogen sulfide (H2S) [lowconcentration] sensor
Hydrogen sulfide (H2S) [highconcentration] sensor
Pump unit (RP-11)
Rubber seals
Tubes

6 months

5 years

1 pc

RX-8500 only*
Shared by RX-8500 and
RX-8700*
RX-8700 only*

6 months

1 year

1 pc

RX-8700 only*

6 months

1 year

1 pc

RX-8700 only*

6 months
6 months

1 - 2 years
2 years
3 - 8 years

1 pc
1 set
1 set

*
*
*
Part number 4777 9025
Protection film (5 pcs)
1 pc
70
About 500 cycles ofLithium ion battery pack1 pc
charging and(For BUL-8000)
discharging
AA type.
Alkaline dry battery
3 pcs
When alkaline dry(For dry battery unit BUD-8000)
battery unit is used.
* The operation must be checked after replacement by a qualified service engineer. For the stable operationof the gas monitor and safety, ask a qualified service engineer to take care of replacement of the parts.
Please contact RIKEN KEIKI.

NOTE

 The above replacement intervals are recommendation only. The intervals may change depending on
the operating conditions. These intervals do not mean the warranty periods either. The result of theregular maintenance may determine when to replace the parts.

- 61 -

8. Storage and Disposal
for a long time

8-1. Procedures to store the gas monitor or leave it

88.

Storage and Disposal

8-1. Procedures to store the gas monitor or leave it
for a long time
The gas monitor must be stored under the following environmental conditions.
• In a dark place under the normal temperature and humidity away from direct sunlight• In a place where gases, solvents, vapors, etc. are not present
Store the gas monitor in a shipping carton, if any, in which the product was delivered.
Store the gas monitor away from dust, etc. if the shipping carton is not available.

CAUTION If the gas monitor is not used for a long time, store it after removing the batteries from the drybattery unit. Leaks from dry batteries may result in fire or injury. If the gas monitor is not used
for a short time, store it without removing the batteries. Since the sensor of the gas monitor isenergized at all times including power-off time, it is necessary to store the gas monitor with thebatteries in it.
 If the gas monitor is not used for a long time, turn on the power at least once every six months
and check that the pump draws in air (about three minutes). The gas monitor, when not
activated for a long time, may cease to work because of hardening of the grease in the pump
motor.

NOTE

 If the gas monitor with the lithium ion battery unit attached is not used for a long time, it isrecommended to store it after discharging the batteries until the battery level icon shows one battery
mark or so. If the gas monitor is stored with the batteries fully charged, the batteries get deteriorated
more quickly and may have shorter life.
 If the gas monitor with the dry battery unit attached is not used for a short time, store it with drybatteries attached. Since the sensor of the gas monitor is energized at all times including power-off
time, it is required to keep dry batteries attached for storage.

8-2. Procedures to use the gas monitor again
When using the gas monitor after storage, perform calibration.

CAUTION
 Contact RIKEN KEIKI for readjustment including calibration.
 If there is a sudden temperature change of 15 ºC or more between the storage and operational
locations, turn on the power of the gas monitor, let it stand for about 10 minutes in a similar
environment to the operational location, and perform air calibration in fresh air before using it.
- 62 -

8. Storage and Disposal

8-3. Disposal of products

8-3. Disposal of products
When the gas monitor is disposed of, it must be treated properly as an industrial waste in accordance withthe local regulations.

WARNING Do not disassemble the carbon monoxide, hydrogen sulfide or oxygen sensor because it
contains electrolyte. Electrolyte may cause severe skin burns if it contacts skin, while it may
cause blindness if it contacts eyes. If electrolyte is adhered on your clothes, that part on yourclothes is discolored or its material is decomposed.
If contact occurs, rinse the area immediately with a large quantity of water. Dispose of batteriesin accordance with procedure specified by the local authority.

<Disposal in EU Member States>
When disposing of the gas monitor in EU member states, sort the batteries as specified.
Handle the batteries removed from the lithium ion battery unit (BUL-8000) or dry batteries used for the drybattery unit (BUD-8000) according to the classified refuse collection system and recycling system based on
the regulations of EU member states.
<Removing battery of lithium ion battery unit>
Remove the lithium ion battery unit with reference to 'Charging the lithium ion battery unit (BUL-8000)' (P.
24).
<Removing batteries>
Remove batteries with reference to 'Attaching batteries to the dry battery unit (BUD-8000, option)' (P. 26).

NOTE
Crossed-out recycle dustbin mark
 This symbol mark is indicated on the products which contain the batteries which fallunder EU Battery Directive 2006/66/EC. Such batteries need to be disposed of as
specified by the latest Directive. This symbol mark indicates that the batteries need
to be separated from the ordinary waste and disposed of appropriately.

- 63 -

9. Troubleshooting

9-1. Abnormalities on unit

99.

Troubleshooting

The troubleshooting does not explain the causes of all the malfunctions which may occur on the gas
monitor. This simply helps to find the causes of malfunctions which may frequently occur.
If the gas monitor shows a symptom which is not explained in this manual, or still has malfunctions eventhough remedial actions are taken, please contact RIKEN KEIKI.

9-1. Abnormalities on unit
Symptoms

CausesActions

The battery level is too low.
The power cannot be
turned on.

Lithium ion battery unit: Charge in a safe
place.
Dry battery unit: Replace all the three drybatteries with new ones in a safe place.

The POWER switch was
released quickly.

For power-on, keep the POWER switch
pressed until a blip is heard.

Improper installation of thebattery unit

Check whether the battery unit is properlyattached to the main unit.

Abnormal operations

Disturbances by sudden
static electricity noise, etc.

Turn off the power once and then turn it on
again (restart).

Cannot operate the gas
monitor.

Disturbances by sudden
static electricity noise, etc.

Remove the battery unit in a safe place.
Then reinstall it and turn on the power toperform operations.

System abnormalities[FAIL SYSTEM]

A circuit abnormality
occurred.

Please contact RIKEN KEIKI for repair.

A sensor has failed.

Please contact RIKEN KEIKI to replace thesensor.(If [FAIL] is displayed in place ofmeasured value at power-on, the alarm canbe reset by pressing the ESC switch. The
operation can be continued using only thenormal sensors to detect other gases.)Sensor abnormalities[FAIL SENSOR]

A low battery voltage
alarm is displayed.
[FAIL BATTERY]

Lithium ion battery unit: Turn off the powerand charge it in a safe place.
The battery level is low.

- 64 -

Dry battery unit: Turn off the power andreplace the dry batteries with new ones in asafe place.

9. Troubleshooting
A low flow rate alarm isdisplayed.
[FAIL LOW FLOW]

Air calibration
impossible[FAIL AIR CAL]

Clock abnormalities[FAIL CLOCK]The batteries cannot becharged.
(Lithium ion battery unit
only)

9-1. Abnormalities on unit
Water, oil or the like isdrawn.

Check the gas sampling hose for any
damage or mark of drawn water, oil, etc.

The gas sampling hose isclogged.

Check the gas sampling hose forconnections, clogging, twisting, etc.

The gas monitor was
powered on at a lowtemperature or has notbeen used for a long time.

Cycle the power several times. The pump
may start operating.

The pump has deteriorated.

Please contact RIKEN KEIKI to replace thepump.

Fresh air is not suppliedaround the gas monitor.

Draw fresh air properly and perform air
calibration again. (P. 37)

A sensor has failed.

Please contact RIKEN KEIKI for repair.

Abnormalities of the internal
clock

Make a setting of date/time.
If a symptom like this is observed
repeatedly, the built-in clock is seemingly
malfunctioning. Thus, it must be replaced.
Please contact RIKEN KEIKI.

The charger is notconnected properly.

Connect the AC plug and DC plug of theAC adapter properly.

A charging circuit
abnormality occurred.

Please contact RIKEN KEIKI for repair..

The batteries have been
fully charged.

When fully charged batteries are charged
again, the charging indicator lamp does not
go on.

- 65 -

9. Troubleshooting

9-2. Abnormalities of readings

9-2. Abnormalities of readings
Symptoms
The reading rises(drops) and it remainsso.

Slow response

Span adjustment
impossible

CausesActions

Drifting of sensor output

Perform the air calibration. (P. 37)

Presence of interferencegas

Disturbances by interference gases, suchas solvents, cannot be eliminatedcompletely. Contact RIKEN KEIKI for
measures to take, such as a use of removal
filter.

Slow leakA very small amount of the gas to bemeasured may be leaking (slow leak).
Because ignoring it may cause dangers,
take actions and measures which are taken
at an occurrence of gas alarm.

Environmental changes

Perform the air calibration. (P. 37)
In particular, the oxygen sensor is affectedby the air pressure.

Clogged dust filter

Replace the dust filter. (P. 59)

Bended or clogged gas
sampling hose

Fix the defective parts.

Condensation is formed
inside the gas monitor.

Fix the defective parts.

Deteriorated sensor
sensitivity

Please contact RIKEN KEIKI to replace thesensor.

Improper calibration gas
concentration

Use the proper calibration gas.

Deteriorated sensor
sensitivity

Please contact RIKEN KEIKI to replace thesensor.

- 66 -

10. Product Specifications

10-1. RX-8500 specifications

10
10.

Product Specifications

10-1. RX-8500 specifications
10-1-1. List of RX-8500 specifications

Measuring gas

Combustible gas(CH4)Oxygen(O2)

Carbon monoxide(CO)

Carbon dioxide(CO2)

Measuring
principle

Non-dispersive
infrared type

Galvanic cell type

Electrochemical
type

Non-dispersive
infrared typeMeasuring range<Service range>

0 - 100.0 %LEL/
5 - 100.0 vol%0 - 25.0 vol%<25.1 - 40.0 vol%>0 - 1000 ppm

0 - 20.0 vol%Minimum
resolution

0.5 %LEL(0 - 100.0 %LEL)
0.5 vol%(5.0 - 100.0 vol%)1 ppm

0.01 vol%(0 - 2.00 vol%)0.05 vol%(2.00 - 5.00 vol%)0.1 vol%(5.00 - 20.0 vol%)Concentration
display
Sampling method
Suction flow rate
Displays
Buzzer soundvolumeFault alarm/self
diagnosis
Fault alarm display
Fault alarm pattern
Transmission
methodFunctionsPower supply
Continuous
operating time
Operatingtemperatures
Operatinghumidities
Structure

0.1 vol%

LCD digital (7-segment + Symbol + Bar meter)
Sample-drawing
0.75 L/min or more (Open flow rate)
Battery level icon, pilot indicator, and pump operation status indicator
95 dB (A) or higher (30 cm)
Low flow rate, battery voltage abnormalities, calibration failure, sensor abnormalities,
system abnormalities and clock abnormalities.
Lamp blinking, intermittent buzzer sounding, and detail display
Self-latching
IrDA (for data logger)
LCD backlight, peak display, pump stop, data logger and log data display
Dedicated lithium ion battery unit [BUL-8000(Z1)] *1<Standard>
Or dedicated dry battery unit <AA alkaline dry battery*2  3> [BUD-8000(Z)] <Option>
BUL-8000 [BUL-8000(Z1)]: About 15 hours (25 °C, no alarm, no lighting and battery
fully charged) <Standard>
BUD-8000 [BUD-8000(Z)]: About 8 hours (25 °C, no alarm and no lighting) <Option>-20 °C - +50 °C
Below 95 %RH (Non-condensing)Drip-proof and dust-proof performances (compliant to IP67 level)- 67 -

10. Product Specifications
Explosion-proof
structure

10-1. RX-8500 specifications

Intrinsically safe explosion-proof structure

Ex ia IIC T4 X（Japan Ex）
II1G Ex ia IIC T4 Ga（ATEX/UKEX）
Ex ia IIC T4 Ga（IECEx）
Dimensions
Approx. 154 (W)  81 (H)  163 (D) mm (projection portions excluded)
About 1.2 kg (with BUL-8000(Z1)) <Standard> or about 1.1 kg (with BUD-8000(Z))
Weight<Option>*1 JG (Japanese Government) type approval is only available for the rechargeable battery type (BUL).
*2 Use Alkaline AA batteries, type LR6 manufactured by Toshiba to meet the conditions for explosion-proof
performance.
* Please refer to the table of correction factors for readings to other gases.
Explosion-proof
class

10-1-2. RX-8500 standard accessories
•
•
•
•
•
•
•
•
•

Lithium ion battery unit
(BUL-8000)
AC adapter for charging
Gas sampling probe and gas
sampling hose
Filter tube (CF-8385)
Relay tube
Absorbing tube fixing belt
Shoulder strap
CO2 removal filter
CO2 filter fixing belt

- 68 -: 1 pc (attached to main unit): 1 pc: 1 pc: 1 pc: 1 pc: 2 pcs: 1 pc: 1 pc: 1 pc10. Product Specifications

10-2. RX-8700 specifications

10-2. RX-8700 specifications
10-2-1. List of RX-8700 specifications
Combustible gas*1(HC)

Oxygen(O2)Hydrogen sulfide(H2S)

Measuring
principle

Non-dispersive
infrared type

Galvanic cell type

Electrochemical typeMeasuring range<Service range>

0 - 100.0 %LEL/
2 - 100.0 vol%0 - 25.0 vol%<25.1 - 40.0 vol%>[Low concentration]
0 - 30.0 ppm<30.5 - 100.0 ppm>

[Highconcentration]
0 - 1000 ppm

Minimum
resolution

0.5 %LEL(0 - 100.0 %LEL)
0.5 vol%(5.0 - 100.0 vol%)0.1 vol%

0.5 ppm

1 ppm

Concentration
display

LCD digital (7-segment + Symbol + Bar meter)

Sampling method

Sample-drawing

Suction flow rate

0.75 L/min or more (Open flow rate)

Displays

Battery level icon, pilot indicator, and pump operation status indicator

Buzzer soundvolumeFault alarm/self
diagnosis

95 dB (A) or higher (30 cm)

Fault alarm display

Lamp blinking, intermittent buzzer sounding, and detail display

Fault alarm pattern

Self-latchingTransmission
methodIrDA (for data logger)

Functions

LCD backlight, peak display, pump stop, data logger and log data display

Measuring gas

Power supply
Continuous
operating time
Operatingtemperatures
Operatinghumidities

Low flow rate, battery voltage abnormalities, calibration failure, sensor abnormalities,
system abnormalities and clock abnormalities.

Dedicated lithium ion battery unit [BUL-8000(Z1)]*2 <Standard>
Or dedicated dry battery unit <AA alkaline dry battery*3  3> [BUD-8000(Z)] <Option>
BUL-8000 [BUL-8000(Z1)]: About 15 hours (25 °C, no alarm, no lighting and battery
fully charged) <Standard>
BUD-8000 [BUD-8000(Z)]: About 8 hours (25 °C, no alarm and no lighting) <Option>-20 °C - +50 °C
Below 95 %RH (Non-condensing)

Structure

Drip-proof and dust-proof performances (compliant to IP67 level)

Explosion-proof
structure

Intrinsically safe explosion-proof structure

Explosion-proof
class

Ex ia IIC T4 X（Japan Ex）
II1G Ex ia IIC T4 Ga（ATEX/UKEX）
Ex ia IIC T4 Ga（IECEx）

Dimensions

Approx. 154 (W)  81 (H)  163 (D) mm (projection portions excluded)

About 1.3 kg (with BUL-8000(Z1)) <Standard> or about 1.2 kg (with BUD-8000(Z))<Option>*1 The combustible gas HC concentration is displayed in isobutane conversion.
*2 JG (Japanese Government) type approval is only available for the rechargeable battery type (BUL).
*3 Use Alkaline AA batteries, type LR6 manufactured by Toshiba to meet the explosion-proof conditions.
* Please refer to the table of correction factors for readings to other gases.
Weight- 69 -

10. Product Specifications

10-2. RX-8700 specifications

10-2-2. RX-8700 standard accessories
•
•
•
•
•
•
•

Lithium ion battery unit
(BUL-8000(Z1))
AC adapter for charging
Gas sampling probe and gas
sampling hose
Filter tube (CF-8385)
Relay tube
Absorbing tube fixing belt
Shoulder strap- 70 -: 1 pc (attached to main unit): 1 pc: 1 pc: 1 pc: 1 pc: 2 pcs: 1 pc10. Product Specifications

10-3. List of optional items

10-3. List of optional items
Sampling probe holder
Waist strap
Waist strap fixing tool
Protection film
Protection film (5 pcs)
Lithium ion battery unit (BUL-8000)
AC adapter
AC adapter replacement plug
Dry battery unit (BUD-8000)
AA alkaline battery (TOSHIBA)
Absorbent cotton (for CF-8385)
Dust filter (10 pcs) (for CF-8385)
Dust filter (10 pcs) (for gas sampling probe)
Data logger management program
Optional items

Demand flow valve(sold separately)

Trap filter
Sampling hose with weight (30 m)
Sampling hose with float (30 m)
Aluminum trunk case (RoHS compliant)Aluminum trunk case (non RoHS compliant)
Shipboard storage box (metal, RoHS compliant)Set of gas sampling bags
Calibration gas can (0.6 L N2: 99.99 % or more)
Calibration gas can (0.6 L i-C4H10: 50 %LEL, Air: balance)
Calibration gas can (0.6 L i-C4H10: 10 %, N2: balance)
Calibration gas can (0.6 L CH4: 70 %LEL, N2: balance)
Calibration gas can (0.6 L CH4: 70 %, N2: balance)
Calibration gas can (0.6 L CO2: 10 %, N2: balance)
Calibration gas can (0.6 L CO: 145 ±5 ppm, N2: balance)
Hydrogen sulfide calibration gas kit (CK-82)

CAUTIONBe sure to use the sampling hose with weight (30 m) in combination with the filter tube
(CF-8385) for dust removal and water-proof performance.
If water, etc. is drawn while the filter tube is unattached, it enters the inside of the unit andcauses a trouble.

- 71 -

11. Appendix

11-1. Definition of terms

11
11.

Appendix11-1. Definition of termsvol%Gas concentration indicated in the unit of one-hundredth of the volumeppm

Gas concentration indicated in the unit of one-millionth of the volume

LEL

The acronym of Lower Explosive Limit.
LEL refers to the lowest concentration of a combustible gas in air capable of causing
explosion when ignited.

Self-latching

One of alarm patterns. Once an alarm is triggered, this keeps the alarm activateduntil it is reset even when the alarm conditions are not met.

11-2. Calibration history/various trend/event history
functions
The gas monitor has history and trend functions. To use this function, please contact RIKEN KEIKI.

NOTE

 The data logger management program (optional) is required to use the history and trend functions.
Contact RIKEN KEIKI for more information.

Data logger provides five functions.

(1) Interval trend
Records the change of measured concentration from power-on to power-off.
Up to 100 latest data are recorded.
After the number of recorded data reaches 100, the oldest data will be overwritten by the latest data.
* However, when the maximum recording time is exceeded, the oldest data will be deleted before reaching
100.
The maximum recording time is specified as follows for each interval time.
10-second 20-second 30-second 1-minute 3-minuteInterval time
10 hours
20 hours
30 hours
60 hours
180
Maximum
hours
recording time
* The standard interval time is "5 minutes."
Interval time can be set by "Data Logger Management Program" (optional).

- 72 -

5-minute
300
hours

10-minute600 hours11. Appendix

11-2. Calibration history/various trend/event history functions(2) Alarm trend
Starting immediately after the alarm is triggered, this function records the change of measured
concentration for one hour, which is from 30 minutes before the alarm was triggered until 30 minutes after
the alarm was triggered.
Alarm trend records the peak value of five-second time at a 5-second interval.
Last eight measurement data shall be recorded.
When the number of data exceeds eight, the oldest data will be overwritten by the latest data.

(3) Alarm event
Records the trigger of alarm as an event.
The event records the time of alarm trigger, target measuring gas and type of alarm event (full scale, first or
second alarm setpoint).
Up to 100 latest events are recorded.
After the number of recorded events reaches 100, the oldest data will be overwritten by the latest data.

(4) Trouble event
Records the trigger of fault alarm as an event.
The event records the time when the trouble was triggered, the target gas of measurement, and the type of
fault event.
Up to 100 latest events are recorded.
After the number of recorded events reaches 100, the oldest data will be overwritten by the latest data.

(5) Calibration history
Records data when the calibration is performed.
The history records the calibration time, concentration values before and after the calibration, as well as thecalibration error.
Up to 100 latest calibration data are recorded.
After the number of recorded data reaches 100, the oldest data will be overwritten by the latest data.

NOTE The data logger function of this gas monitor is entirely based on the overwriting system (the oldest
data is deleted and the latest data is recorded).
 The recorded data can be read out by the "Data Logger Management Program" (optional). See theoperating manual of "Data Logger Management Program" for more information.

- 73 -

11. Appendix

11-3. Gas alarm (optional function)

11-3. Gas alarm (optional function)
Normally the gas alarm function is set to OFF and unavailable (optional function). To use this function,please contact RIKEN KEIKI.
Gas alarm: Triggered when the concentration of detected gas reaches or exceeds the alarm setpoint value.
(Self-latching)
Alarm display: Notifies users of an alarm by blinking the concentration display of the subject gas, sounding
the buzzer and lighting the lamp.
Alarm types: First alarm (WARNING), second alarm (ALARM) and OVER alarm<List of Gas Alarms>
Gas alarm type

Sounding buzzer

Blinking alarm LED
arraysLCD display

First alarm
Repeatedly sounds
strong and weak beeps
at about 1-second
intervals.
"Beep, beep"
Repeatedly blinks at
about 1-second intervals.
Blinks the gas
concentration and[WARNING] displays.

Second alarm
Repeatedly sounds
strong and weak beeps atabout 0.5 second
intervals:"Beep, beep, beep, beep"
Repeatedly blinks at
about 0.5-second
intervals.
Blinks the gas
concentration and[ALARM] displays.

- 74 -

OVER alarm
Repeatedly sounds
strong and weak beeps atabout 0.5 second
intervals:"Beep, beep, beep, beep"
Repeatedly blinks at
about 0.5-second
intervals.
Blinks the gas
concentration and[OVER] displays.

11. Appendix

11-3. Gas alarm (optional function)- 75 -

11. Appendix

11-3. Gas alarm (optional function)- 76 -